Granulated acetylene black, process for its production and its application

Abstract

Granulated acetylene black having a bead strength of at least 5 g/grain, a bulk density of at least 0.2 g/cm3 and a grit content of at most 10 ppm.

What is claimed is: 
     
       1. Granulated acetylene black having a coating layer of acetylene black formed on the surface of particulate acetylene black, wherein said granulated acetylene black has a bead strength of at least 5 g/grain, and   said coating layer is denser than said particulate.   
     
     
       2. The granulated acetylene black according to claim 1, which has a bead strength of at least 5 g/grain, a bulk density of at least 0.2 g/cm 3  and a grit content of at most 10 ppm. 
     
     
       3. The granulated acetylene black according to claim 2, which has an ash content of at most 100 ppm. 
     
     
       4. The granulated acetylene black according to claim 1, which has a bead strength of from 5 to 10 g/grain, a bulk density of from 0.25 to 0.4 g/cm 3 , a grit content of at most 10 ppm and an ash content of at most 50 ppm. 
     
     
       5. The granulated acetylene black according to claim 4, wherein the grit content is at most 1 ppm. 
     
     
       6. The granulated acetylene black of claim 1, wherein said granulated acetylene black has a bead strength of at least 6.9 g/grain. 
     
     
       7. The granulated acetylene black of claim 1, wherein said coating layer is prepared by blending from 10 to 50 parts by weight of acetylene black feed powder to 100 parts by weight of a granulated acetylene black product, followed by granulation in a second stage. 
     
     
       8. A process for producing the granulated acetylene black, of claim 1 which comprises blending from 200 to 350 parts by weight of deionized water to 100 parts by weight of acetylene black feed powder, followed by granulation in a first stage to obtain a granulated product, and then blending from 10 to 50 parts by weight in acetylene black feed powder to 100 parts by weight of the granulated product, followed by granulation in a second stage. 
     
     
       9. A composition comprising a resin and/or rubber, and the granulated acetylene black as defined in claim 1, incorporated thereto. 
     
     
       10. A composition for a semi-conductive shield for a cable, comprising a resin and/or rubber which is at least one member selected from the group consisting of an ethylene/vinyl acetate copolymer, an ethylene/ethyl acrylate copolymer and an ethylene/butyl acrylate copolymer, in a total amount of 100 parts by weight, and the granulated acetylene black as defined in claim 1, blended thereto, in an amount of from 30 to 100 parts by weight.